The invention relates to an evaluation method for a sequence of movement commands,                wherein the movement commands each define a position to be adopted by a tool of a processing machine relative to a workpiece,        wherein during the execution of the sequence of movement commands by a control device of the processing machine, the tool machines the workpiece at least intermittently,        wherein the movement commands, during their execution by the control device of the processing machine, are converted into a trajectory including the defined positions,        wherein a depiction of the trajectory defined by the sequence of movement commands is output to a user.        
Within the scope of the present invention, “positions” means exclusively a translational positioning of the tool relative to the workpiece. If an orientation of the tool relative to the workpiece is meant, the corresponding term (“orientation”) is also used. The term “position” can either be an exclusive translational positioning of the tool relative to the workpiece or a translational positioning of the tool relative to the workpiece, in which an orientation of the tool relative to the workpiece is additionally also set.
The present invention also starts from a computer program comprising machine code which can be executed by an arithmetic device, wherein the execution of the machine code by means of the arithmetic device causes the arithmetic device to execute such an evaluation method.
The present invention also starts from an arithmetic device, wherein the arithmetic device is programmed with a computer program such that it executes an evaluation method of this kind.
Within the framework of the creation of parts programs—in other words programs by means of which numerical control devices control processing machines, so that these machining operations can be carried out on workpieces—a CAD data set is generally created first of all (CAD=Computer Aided Design). The corresponding CAD data set defines the shape of the workpiece to be produced. However, it generally does not include any information about the machining processes required for this purpose. The CAD data set is therefore converted into a CAM data set by means of an arithmetic device (CAM=Computer Aided Manufacturing). The CAM data set defines the parts program to be executed later. It comprises a plurality of sequences of movement commands within the meaning of the present invention.
Theoretically, the conversion of the CAD data set into the CAM data set is perfect. The same applies to subsequent process steps. In practice, however, it can happen that subsequent machining of the workpiece leads to surface defects. The causes of such surface defects are diverse in nature. In particular, however, it can often no longer be possible to see on the workpiece which specific individual machining process has caused the respective surface defect.
A method for depicting, examining and optimizing a surface quality on the basis of CNC program data is known from EP 1 315 058 058 A1. In this method, the CNC program data describes track points of space curves. The associated normal vectors are determined and displayed for a plurality of adjacent track points. Normal vectors, which are directed substantially in the same direction, indicate regions of high surface quality, while normal vectors which point in (clearly) deviating directions indicate inaccuracies of the resulting surface.
The method of EP 1 315 058 A1 already leads to a significant improvement in the conversion of the CAD data set into the CAM data set. In particular, locations of the CAM data set which bring about an insufficient quality of the surface of the machined workpiece can be identified. However, the method of EP 1 315 058 A1 does not lead to the desired result in all cases.
The object of the present invention is to create an evaluation method with which the locations of the CAM data set, whose execution can lead to a reduced surface quality of the machine workpiece, can be reliably and comprehensively identified.
The object is achieved by an evaluation method having the features of claim 1. Advantageous embodiments of the evaluation method are the subject matter of dependent claims 2 to 13.
The object is achieved by an evaluation method of the type mentioned in the introduction and being inventively configured in that                the distances between the positions of directly successive movement commands are ascertained,        positions of directly successive movement commands, whose distance is below a predetermined minimum distance, are highlighted in the depiction by means of a marker.        
Advantageous embodiments of the evaluation method are the subject matter of dependent claims.
This approach is based on the knowledge that, during the conversion of the CAD data set into the CAM data set, the support points (=defined positions), between which interpolation is carried out by the control device during the course of the execution of the sequence of movement commands, are generally far apart from each other for processing operations to be carried out without any problems. In the case of machining processes which are difficult to carry out, on the other hand, a large number of closely successive positions must be approached. Such facts often cause surface defects.
In some cases (for example in some three-axis machine tools) a movement of the tool relative to the workpiece is only possible in the three translational directions. In other cases (for example in the case of some five-axis machine tools) an adjustment of the orientation of the tool relative to the workpiece is also possible. In the last-mentioned cases, the movement commands also define an orientation to be adopted by the tool relative to the workpiece in addition to the respective position. Furthermore, in these cases the movement commands are converted during their execution by the control device of the processing machine in such a way that the tool adopts the corresponding orientation relative to the workpiece at the defined positions.
It is possible, even in such cases, to limit the evaluation to the position as such. Preferably, in such cases the method is, however, configured in that                In addition, the change in the orientation of directly successive movement commands is determined and        positions of directly successive movement commands, whose change in orientation is above a first maximum change, are highlighted by means of a marker.        
It is possible for the first maximum change to be predetermined, in other words, always to have the same value. Preferably, however, the first maximum change is determined as a function of the distance between the positions of the respective directly successive movement commands.
An even more extensive evaluation of the orientations is also possible. In particular it is possible                that pairs of movement commands, whose respective position is below a predetermined first minimum distance, are respectively determined for the positions to be adopted by the tool,        that the difference in the orientations to be adopted by the tool relative to the workpiece is determined for the pairs of movement commands, and        that positions of pairs of movement commands, in which the difference in the orientations is above a second maximum change, are highlighted by means of a marker.        
This type of evaluation leads to an even more comprehensive evaluation of the movement commands.
Analogously to the first maximum change, it is possible that the second maximum change is determined as a function of the distance between the positions of the two movement commands of the respective pair of movement commands.
As a rule, the movement commands, in addition to the respective position, not only define an orientation to be adopted by the tool relative to the workpiece, but also a respective direction of movement. In particular, the movement commands are converted during their execution by the control device of the processing machine in such a way that the tool not only adopts the corresponding orientation relative to the workpiece at the defined positions, but also in the corresponding direction of movement. In this case, the evaluation method is preferably designed in such a way that                for the positions to be adopted by the tool, in addition the cross product in the direction of movement and the orientation respectively is determined,        the change in the direction of the cross product of directly successive movement commands is determined and        positions of directly successive movement commands, whose change in the direction of the cross product is above a third maximum change, are highlighted by means of a marker.        
This type of evaluation leads to an even more comprehensive evaluation of the movement commands.
Analogously to the first maximum change it is possible that the third maximum change is determined as a function of the distance between the positions of the respective directly successive movement commands.
Just as with the orientations, it is possible that                pairs of movement commands, whose respective position is below a predetermined second minimum distance, are respectively determined for the positions to be adopted by the tool,        the difference in the directions of the cross product is determined for the pairs of movement commands, and        positions of pairs of movement commands in which the difference in the directions of the cross products is above a fourth maximum change are highlighted by means of a marker.        
This type of evaluation leads to an even more comprehensive evaluation of the movement commands.
Analogously to the second maximum change it is possible that the fourth maximum change is determined as a function of the distance between the positions of the two movement commands of the respective pair of movement commands.
If the movement commands, in addition to the respective position, define an orientation to be adopted by the tool relative to the workpiece and a respective direction of movement, the evaluation method can also be designed in such a way that                using the direction of movement and the orientation, in addition a normal vector oriented orthogonally to the surface of the workpiece at the respective position is determined for the positions to be adopted by the tool,        the change in the direction of the normal vector of directly successive movement commands is determined and        positions of directly successive movement commands, whose change in direction of the normal vector is above a fifth maximum change, are highlighted by means of a marker.        
Analogously to the first maximum change it is possible that the fifth maximum change is determined as a function of the distance between the positions of the respective directly successive movement commands.
Furthermore, it is additionally possible in this case that                pairs of movement commands, whose respective position is below a predetermined third minimum distance, are respectively determined for the positions to be adopted by the tool,        the difference in the directions of the normal vectors is determined for the pairs of movement commands and        positions of pairs of movement commands in which the difference in the directions of the normal vectors is above a sixth maximum change are highlighted by means of a marker.        
Analogously to the first maximum change it is possible that the sixth maximum change is determined as a function of the distance between the positions of the respective directly successive movement commands.
The object is further achieved by a computer program including machine code which can be executed by an arithmetic device, in such a way that the execution of the computer program by means of the arithmetic device causes the arithmetic device to execute an inventive evaluation method.
The object is further achieved by an arithmetic device which is programmed with an inventive computer program so it executes an inventive evaluation method during operation.